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| Titel |
Phosphate supply explains variation in nucleic acid allocation but not C : P stoichiometry in the western North Atlantic |
| VerfasserIn |
A. E. Zimmerman, A. C. Martiny, M. W. Lomas, S. D. Allison |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 6 ; Nr. 11, no. 6 (2014-03-26), S.1599-1611 |
| Datensatznummer |
250117307
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| Publikation (Nr.) |
 copernicus.org/bg-11-1599-2014.pdf |
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| Zusammenfassung |
| Marine microbial communities mediate many biogeochemical transformations in
the ocean. Consequently, processes such as primary production and carbon (C)
export are linked to nutrient regeneration and are influenced by the resource
demand and elemental composition of marine microbial biomass. Laboratory
studies have demonstrated that differential partitioning of element resources
to various cellular components can directly influence overall cellular
elemental ratios, especially with respect to growth machinery (i.e.,
ribosomal RNA) and phosphorus (P) allocation. To investigate whether
allocation to RNA is related to biomass P content and overall C : P biomass
composition in the open ocean, we characterized patterns of P allocation and
C : P elemental ratios along an environmental gradient of phosphate supply
in the North Atlantic subtropical gyre (NASG) from 35.67° N,
64.17° W to 22.676° N, 65.526° W. Because the NASG is
characterized as a P-stressed ecosystem, we hypothesized that biochemical
allocation would reflect sensitivity to bioavailable phosphate, such that
greater phosphate supply would result in increased allocation toward P-rich
RNA for growth. We predicted these changes in allocation would also result in
lower C : P ratios with increased phosphate supply. However, bulk C : P
ratios were decoupled from allocation to nucleic acids and did not appear to
vary systematically across a phosphate supply gradient of
2.2–14.7 μmol m−2 d−1. Overall, we found that C : P ratios ranged from
188 to 306 along the transect, and RNA represented only 6–12% of total
particulate P, whereas DNA represented 11–19%. We did find that
allocation to RNA was positively correlated with phosphate supply rate,
suggesting a consistent physiological response in biochemical allocation to
resource supply within the whole community. These results suggest that
community composition and/or nonnucleic acid P pools may influence
ecosystem-scale variation in C : P stoichiometry more than nucleic acid allocation or
P supply in diverse marine microbial communities. |
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